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<pre>
      SUBROUTINE <a name="CLACRT.1"></a><a href="clacrt.f.html#CLACRT.1">CLACRT</a>( N, CX, INCX, CY, INCY, C, S )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  -- LAPACK auxiliary routine (version 3.1) --
</span><span class="comment">*</span><span class="comment">     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
</span><span class="comment">*</span><span class="comment">     November 2006
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Scalar Arguments ..
</span>      INTEGER            INCX, INCY, N
      COMPLEX            C, S
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Array Arguments ..
</span>      COMPLEX            CX( * ), CY( * )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Purpose
</span><span class="comment">*</span><span class="comment">  =======
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  <a name="CLACRT.18"></a><a href="clacrt.f.html#CLACRT.1">CLACRT</a> performs the operation
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     (  c  s )( x )  ==&gt; ( x )
</span><span class="comment">*</span><span class="comment">     ( -s  c )( y )      ( y )
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  where c and s are complex and the vectors x and y are complex.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  Arguments
</span><span class="comment">*</span><span class="comment">  =========
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  N       (input) INTEGER
</span><span class="comment">*</span><span class="comment">          The number of elements in the vectors CX and CY.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  CX      (input/output) COMPLEX array, dimension (N)
</span><span class="comment">*</span><span class="comment">          On input, the vector x.
</span><span class="comment">*</span><span class="comment">          On output, CX is overwritten with c*x + s*y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCX    (input) INTEGER
</span><span class="comment">*</span><span class="comment">          The increment between successive values of CX.  INCX &lt;&gt; 0.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  CY      (input/output) COMPLEX array, dimension (N)
</span><span class="comment">*</span><span class="comment">          On input, the vector y.
</span><span class="comment">*</span><span class="comment">          On output, CY is overwritten with -s*x + c*y.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INCY    (input) INTEGER
</span><span class="comment">*</span><span class="comment">          The increment between successive values of CY.  INCY &lt;&gt; 0.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  C       (input) COMPLEX
</span><span class="comment">*</span><span class="comment">  S       (input) COMPLEX
</span><span class="comment">*</span><span class="comment">          C and S define the matrix
</span><span class="comment">*</span><span class="comment">             [  C   S  ].
</span><span class="comment">*</span><span class="comment">             [ -S   C  ]
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment"> =====================================================================
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      INTEGER            I, IX, IY
      COMPLEX            CTEMP
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Executable Statements ..
</span><span class="comment">*</span><span class="comment">
</span>      IF( N.LE.0 )
     $   RETURN
      IF( INCX.EQ.1 .AND. INCY.EQ.1 )
     $   GO TO 20
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Code for unequal increments or equal increments not equal to 1
</span><span class="comment">*</span><span class="comment">
</span>      IX = 1
      IY = 1
      IF( INCX.LT.0 )
     $   IX = ( -N+1 )*INCX + 1
      IF( INCY.LT.0 )
     $   IY = ( -N+1 )*INCY + 1
      DO 10 I = 1, N
         CTEMP = C*CX( IX ) + S*CY( IY )
         CY( IY ) = C*CY( IY ) - S*CX( IX )
         CX( IX ) = CTEMP
         IX = IX + INCX
         IY = IY + INCY
   10 CONTINUE
      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Code for both increments equal to 1
</span><span class="comment">*</span><span class="comment">
</span>   20 CONTINUE
      DO 30 I = 1, N
         CTEMP = C*CX( I ) + S*CY( I )
         CY( I ) = C*CY( I ) - S*CX( I )
         CX( I ) = CTEMP
   30 CONTINUE
      RETURN
      END

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